For example, if a method's argument enables or disables fields with personal information then call it enablePersonalInfo - you should describe what the argument is doing or which information it brings, you don't need to explain other programmers what Boolean type is! The only exception to this rule - if the meaning of the Boolean argument is conveyed by the method's name: for example, the method SetReadOnlyMode() can have an argument named simply switchIt (so it's understood that passing false cancels the mode).